Center guided tile drill

ABSTRACT

A self centering drill or hole saw particularly useful for drilling ceramic tile and removing grout from around a valve is described. The drill has an annular drilling face at one end of a hollow cylinder and is centered by a mandrel having a bore which fits over a valve stem. A cap on the mandrel provides adjustment for different size valve stems.

United States Patent [191 Viscovich 1 1 CENTER GUIDED TILE DRILL [75] Inventor: Steven J. Viscovich, Los Angeles,

Calif.

[73] Assignee: Relton Corporation, Arcadia, Calif.

[22] Filed: Dec. 8, 1972 [21] Appl. No.: 313,249

[52] US. Cl. 175/403, 175/410 [51] Int. Cl. E2lb 9/16, E2lc 13/02 [58] Field of Search 175/262, 220, 330,403, 175/53, 80, 410; 408/84, 204

[56] References Cited UNITED STATES PATENTS 1,484,352 2/1924 lzard 175/403 X 2,298,975 10/1942 Shelburne... 175/403 X 3,217,816. 11/1965 Boyer l75 /403 X 1 May 14, 1974 2,599,770 6/1952 Marcerou 175/403 X 1,316,201 9/1919 Tacke 408/84 X 1,456,983 5/1923 Hansen 175/403 X 2,827,264 3/1958 Sitton et a1. 175/403 X 2,969,122 l/l96l Steffes 175/403 X Primary Examiner-David H. Brown Attorney, Agent, or Firm-Christie, Parker & Hale [5 7 ABSTRACT A self centering drill or hole saw particularly useful for drilling ceramic tile and removing grout from around a valve is described. The drill has an annular drilling face at one end of a hollow cylinder and is centered by a mandrel having a bore which fits over a valve stem. A cap on the mandrel provides adjustment for different size valve stems.

9 Claims, 3 Drawing Figures l CENTER GUIDED TILE DRILL,

BACKGROUND In many household installations valves are embedded in a wall that is subsequently covered with ceramic tile. Thus, for example, it is fairly common for the hot and cold water valves for a bathtub to be mounted within the wall with only their stems protruding into the room. The wall is subsequently covered with ceramic tile held in place by a ceramic grout. Typically the person installing the tile makes a cut only large enough to permit clear passage of the valve stem.

Months or years later when replacement of gaskets within the valve becomes necessary, access to the valve is restricted by the overlying tile. The usual practice has been to very slowly and tediously chip away the tile around the valve stem with a chisel to enlarge the hole enough for a socket wrench to fit on the valve bonnet nut. The chipping of the tile is a painstaking job usually requiring from one-half to three-fourths of an hour per valve. This is necessary since only tiny blows can be delivered to the tile to keep from causing a crack that might extent beyond the decorative escutcheon normally installed over the valve stem. Despite the utmost precaution tile cracking and chipping may'still occur.

it is therefore highly desirable to have a means for enlarging the hole around the valve stem to permit a socket to be placed on the bonnet nut of the valve. This enlargement should be done rapidly'and safely without significant danger of chipping or cracking the tile. Preferably such a means is economical and easily manufactured and has long life in field service. Such means should also be adaptable to a variety of household situations since there is only limited standardization in this area.

BRIEF SUMMARY-OF THE INVENTION There is, therefore, provided in practice of this. invention according to a presently preferred embodiment a tile drill for removing tile and grout from around the valve stem of a valve embedded in a tile wall comprising a hollow cylinder closed at one end and open at the other end with an annular tile cutting face around the open end. The closed end of the cylinder is connectable to a rotatable drive such as a hand-held electric drill.

Means are provided within the cylinder and recessed from the open end thereof for maintaining the cylinder in alignment with the valve stem while permitting translation and rotation of the cylinder relative to the valve stem.

DRAWINGS These and other features and advantages of the pres ent invention will be appreciated as. the same becomes better understood by reference to the following de- DESCRIPTION FIGS. 1 and 2 illustrate in longitudinal cross section and end view respectively a tile drill constructed according to principles of this invention. As illustrated in this presently preferred embodiment the tile drill has a central mandrel 10 having a reduced diameter shank 11 at the rearward end thereof. The shank is typically cylindrical but may include three symmetrically placed flat portions for engagement by the jaws of a conventional Jacobs chuck. The tool is used by mounting the shank in a conventional or k inch electric drill, preferably the latter since lower rotational speeds are typically available. The mandrel 10 is provided with a male thread from its forward end over much or all of its length. Threads extending the full length of the mandrel may be desirable to permit disassembly if the threads at the forward end of the mandrel become damaged. An axial bore 24 extends along the mandrel from the forward end thereof.

A hollow cylindrical cutter 12 is threaded onto the mandrel. The cylinder is closed at its rearward end where it is fitted onto the mandrel. If desired, holes can be left in the rearward end to permit discharge of chips and dust, however, this has not been found necessary in practice. The opposite or forward end of the cylinder 12 is open and has six tungsten carbide or other hard inserts l3 embedded therein. The tungsten car-. bide inserts typically have a cutting angle of about 18 to 20 and are ground or mounted at an angle in the end of the cylinder to give a negative rake of about 5 which appears to be best for cutting ceramic tile. The hard inserts 13 collectively form an annular tile cutting face at the open end of the cylinder. If desired a helical groove dust worm can be provided on the exterior of the cylinder for carrying dust and small chips away from the cutting face. No real need for this has been found in practice however.

' The hollow cylinder 12 is threaded onto the mandrel so that the forward end of the mandrel is recessed an inch or so from the open end of the cylinder. A jam nut 14 is then tightened against the cylinder to hold it in place. Transverse holes 16 may be provided through the cylinder to hold it during tightening of the jam nut and to aid in threading it on and off the mandrel. The normal rotation of the drill as it is used tends to tighten the cylinder against the jam nut and inhibit motion on the threads.

FIG. 1 illustrates the tilev drill opposite a typical embedded faucet to illustrate the mode of operation thereof. Thus a conventional water valve 17 may be embedded in a wall with ceramic tile 18 forming the face of the wall. A thick layer of grout 19 is typically present between the tile and the bonnet nut 21 of the valve. The valve stem 22 extends through a small hole 23 in the ceramic tile. Typically the hole through the tile and the pack of grout behind it is so small that a socket cannot be fitted in for removing the bonnet nut. In typical household applications the valve stem 22 has a diameter of either three-eighths inch or sevensixteenths inch.

When the tile drill is used the axial bore 24 in the mandrel 10 is fitted over the valve stem 22. The diamter of the bore in the mandrel is slightly over seven-sixteenths inch so that it fits closely on a sevensixteenths inch diameter valve stem. The bore is also sufficiently deep that it will accommodate the full length of the valve stem when the drill is used. This perand along the valve stem while the stem serves to center and guide the drill. The stem within the mandrel keeps the cylinder from wandering relative to the tile as a hole is drilled. This is of considerable importance since, unless the drill is so guided, cracking or shattering of the tile will almost certainly occur.

The end of the mandrel is recessed from the annular cutting'face of the cylinder so that clearance for the bonnet nut is provided. The set back of the mandrel from the cutting face is small enough that guidance of thedrill is obtained throughout its stroke as a hole is drilled. It will be noted that the inside diameter of the cylinder is sufficient to clear the outermost extent of the bonnet nut. This permits clean cutting of the grout from around the nut clear down to the valve body. Typ ically the grout caked onto the nut is relatively fragile and much of it chips off during the drilling operation. The balance is quite quickly and safely removed after the hole has been cut by the usual chipping techniques.

As mentioned above, household valve stems may also have a diameter of three-eighths inch. The clearance between a seven-sixteenths. inch bore and a threeeighths inch valvestem is sufficient that the drill can wander and damage to vthe tile may occur. When it is desired to use the drill with a three-eighths valve stem, a cap 26 is threaded onto the mandrel. The cap 26 has a central aperture 27 having a diameter of slightly over three-eighths inch The cap thus serves to center the drill relativeto the valve stem to prevent wandering during use.

lf desiredthe bore 24 within the mandrel can be noticeably larger than seven-sixteenths inch and a cap having a central aperture with a diameter of sevensixteenths inch can be threaded on the end when a sev- 4 en-sixteenths inch valve stem is found. This has the advantage of providing centering of the drill while limiting rubbing between the interior of the bore and the valve stem. The use of a cap on the end of the mandrel at all times also protects the threads on the mandrel from the abrasive action of tile and grout particles. I

- HO. 3 illustrates in a fragmentary view the forward end of a mandrel 28 slightly modified from that hereinabove described and illustrated in FIG. I. The forward end of the mandrel 28 has a diameter smaller than the balance of the length and a plastic cap 29 is slipped onto this reduced end. This plastic cap 29 has a central aperture 31 which -may have a diameter of threeeighths or seven-sixteenths inch as may be suitable for a particular drilling operation. Such plastic caps are inexpensive and easily installed and are quite-suitable for guiding the tile drill relative to the valve stem during use of the drill. The plastic caps have the further advantage of inhibiting any tendency to score the valve stem.

Although limited embodiments of a tile drill constructed according to principles of this invention have been described and illustrated herein many modifications and variations will be apparent to one skilled in the art. Thus, for example, instead of using the hard tungsten carbide inserts in the annular cutting face, diamond or other hard abrasive particles may be embedded in the end of the cylinder. Other arrangements for mounting the cylinder on the mandrel in an .arbitrarily selected position for recessing the end of the mandrel beyond the open end of .the cylinder may also be provided. Many other modifications and variations will be apparent to one skilled in the art and it is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. 1

What is claimed is:

l. A tile drill for removing tile and grout around the valve stem of a valve embedded in a tiled wall comprising:

a threaded mandrel;

shank means at one end of the mandrel for connection to a rotatable drive;

i a hollow cylinder having one end threaded onto the mandrel an arbitrary distance so that the shank means is external to the cylinder and the opposite end of the mandrel is within the cylinder, the opposite end of the cylinder being open;

a plurality of hard inserts around the open end of the cylinder for cutting tile;

a jam nut on the mandrel for securing the cylinder in the arbitrary position;

a bore in the mandrel coaxial with the cylinder for re- 4. A tile drill as defined in claim 3 wherein the cap I is threaded onto the end of the mandrel.

5. A tile drill as defined in claim 3 wherein the cap comprises a plastic member slipped onto the end of the mandrel.

6. A tile drill for removing tile and grout around the valve stem of a valve embedded in a tiled wall comprisa hollow cylinder closed at one end and open at the other end;

an annular cutting face around the open end of the cylinder for cutting tile;

means at the closed end of the cylinder for connection to a rotatable drive;

means within the cylinder and recessed from the open end thereof for maintaining the cylinder in alignment with the valve stem while permitting.

translation and rotation of the cylinder relative to the valve stem comprising a mandrel coaxial with the cylinder and a bore in the mandrel for receiving the valve stem.

7. A tile drill for removing tile and grout around the valve stem of a valve embedded in a tiled wall comprismg:

a hollow cylinder closed at one end and open at the other end;

an annular cutting face around the open end of the cylinder for cutting tile; means at the closed end of the cylinder for connection to a rotatable drive;

a mandrel coaxial with and within the cylinder and recessed from the open end thereof;

a bore in the mandrel for receiving the valve stem;

and

a cap on the end of the mandrel having acentral aperture having a diameter substantially the same as the diameter of a conventional valve stemand valve stem of a valve embedded in a tiled wall comprising:

a hollow cylinder closed at one end and open at the other end; an annular cutting face around the open end of'the cylinder for cutting tile;

means at the closed end of the cylinder for connection to a rotatable drive; and v a mandrel coaxial with and within the cylinder and recessed from the open end thereof, a bore in the mandrel for receiving the valve stem, and a cap on the end of the mandrel having a central aperture having a diameter substantially the same as the diameter of a conventional valve stem for maintain- 6 ing the cylinder in alignment with the valve stem while permitting translation and rotation of the cylinder relative to the valve stem; and wherein the mandrel has a male thread, the cylinder has a fe male thread fitted on the mandrel and the cap fits on the threaded mandrel.

9. A tile drill for removing tile and grout around the valve stem ofa valve embedded in a tiled wall comprising:

a hollow cylinder closed at one end and open at the other end;

an annular cutting face around the open end of the cylinder for cutting tile;

means at the closed end of the cylinder for connection to a rotatable drive;

means' within the cylinder and recessed from the open end thereof for maintaining the cylinder in alignment with the valve stem while permitting translation and rotation of the cylinder relative to the valve stem; and

means for adjusting the depth of recess from the end of the cylinder of the means for maintaining align- 

1. A tile drill for removing tile and grout around the valve stem of a valve embedded in a tiled wall comprising: a threaded mandrel; shank means at one end of the mandrel for connection to a rotatable drive; a hollow cylinder having one end threaded onto the mandrel an arbitrary distance so that the shank means is external to the cylinder and the opposite end of the mandrel is within the cylinder, the opposite end of the cylinder being open; a plurality of hard inserts around the open end of the cylinder for cutting tile; a jam nut on the mandrel for securing the cylinder iN the arbitrary position; a bore in the mandrel coaxial with the cylinder for receiving the valve stem; and means for maintaining the bore axially positioned relative to the valve stem.
 2. A tile drill as defined in claim 1 wherein the means for maintaining comprises a bore having a diameter substantially the same as the diameter of a conventional valve stem.
 3. A tile drill as defined in claim 1 wherein the means for maintaining comprises a cap on the end of the mandrel, said cap having a central aperture having a diameter substantially the same as the diameter of a conventional valve stem.
 4. A tile drill as defined in claim 3 wherein the cap is threaded onto the end of the mandrel.
 5. A tile drill as defined in claim 3 wherein the cap comprises a plastic member slipped onto the end of the mandrel.
 6. A tile drill for removing tile and grout around the valve stem of a valve embedded in a tiled wall comprising: a hollow cylinder closed at one end and open at the other end; an annular cutting face around the open end of the cylinder for cutting tile; means at the closed end of the cylinder for connection to a rotatable drive; means within the cylinder and recessed from the open end thereof for maintaining the cylinder in alignment with the valve stem while permitting translation and rotation of the cylinder relative to the valve stem comprising a mandrel coaxial with the cylinder and a bore in the mandrel for receiving the valve stem.
 7. A tile drill for removing tile and grout around the valve stem of a valve embedded in a tiled wall comprising: a hollow cylinder closed at one end and open at the other end; an annular cutting face around the open end of the cylinder for cutting tile; means at the closed end of the cylinder for connection to a rotatable drive; a mandrel coaxial with and within the cylinder and recessed from the open end thereof; a bore in the mandrel for receiving the valve stem; and a cap on the end of the mandrel having a central aperture having a diameter substantially the same as the diameter of a conventional valve stem and smaller than the bore in the mandrel for maintaining the cylinder in alignment with the valve stem while permitting translation and rotation of the cylinder relative to the valve stem.
 8. A tile drill for removing tile and grout around the valve stem of a valve embedded in a tiled wall comprising: a hollow cylinder closed at one end and open at the other end; an annular cutting face around the open end of the cylinder for cutting tile; means at the closed end of the cylinder for connection to a rotatable drive; and a mandrel coaxial with and within the cylinder and recessed from the open end thereof, a bore in the mandrel for receiving the valve stem, and a cap on the end of the mandrel having a central aperture having a diameter substantially the same as the diameter of a conventional valve stem for maintaining the cylinder in alignment with the valve stem while permitting translation and rotation of the cylinder relative to the valve stem; and wherein the mandrel has a male thread, the cylinder has a female thread fitted on the mandrel and the cap fits on the threaded mandrel.
 9. A tile drill for removing tile and grout around the valve stem of a valve embedded in a tiled wall comprising: a hollow cylinder closed at one end and open at the other end; an annular cutting face around the open end of the cylinder for cutting tile; means at the closed end of the cylinder for connection to a rotatable drive; means within the cylinder and recessed from the open end thereof for maintaining the cylinder in alignment with the valve stem while permitting translation and rotation of the cylinder relative to the valve stem; and means for adjusting the depth of recess from the end of the cylinder of the means for maintaining alignment. 